Caption: Shigella dysenteriae. Coloured transmission electron micrograph (TEM) of Shigella dysenteriae bacteria, the cause of dysentery in humans. A longitudinal section through a bacterial cell is seen (at centre). Dysentery affects mainly the large intestines and varies in severity from a mild attack of diarrhoea to an acute infection. Until the introduction of sulphonamide drugs in the 1930s it was a killer disease of the world. It still affects the young, elderly & malnourished. Infection is spread by flies, direct contact, & water contaminated by faeces containing the bacillus. Magnification: x38,000 a 6x7cm size. x125,000 at 8x10 "